2. On the Colouring Matter of Persian Berries

Extract

Two varieties of the seeds of the Rhamnus tinctoria are found in commerce, known by the names of Persian and Turkish berries. The former are said to be gathered before being fully ripe, and are carefully preserved; the latter have remained much longer on the branches, and are brown and shrivelled. Kane has examined both varieties, and finds in the former a substance which he names Chrysorhamnine, soluble in alcohol and ether, and crystallizing from the latter in minute silky needles of a brilliant yellow colour. This substance is replaced in the ripe berry by another, which he names Xanthorhamnine, of a much less beautiful yellow, and not crystallizable; this change is effected also by boiling the chrysorhamnine for a few minutes with water. Xanthorhamnine is easily soluble in alcohol and water, but quite insoluble in ether.